Fibrofatty tissue cores infiltrated by malignant epithelial cells arranged in groups and cords, with focal glandular differentiation. The tumor exhibits moderate anaplasia and increased mitotic activity. The surrounding stroma demonstrates a mild desmoplastic response. No lymphoid tissue is identified in the examined material.
The histomorphologic features are consistent with a moderately differentiated adenocarcinoma (Grade 2). The primary site cannot be definitively determined, and the differential diagnosis includes a primary breast (tail of Spence) carcinoma versus metastatic adenocarcinoma involving axillary lymph nodes. Clinicoradiologic correlation, particularly with mammographic findings, is recommended, along with immunohistochemical studies (GATA3, TTF-1, ER, PR, CK7, and CK20) .
Axillary mass.
Tissue cores up to 1.5 cm, long.